This nonprovisional application claims priority under 35 U.S.C. xc2xa7119(a) on Patent Application No. 2001-304032 filed in JAPAN on Sep. 28, 2001, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a toner used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing method, and the like.
2. Discussion of the Related Art
In order to aim for improvement in the low-temperature fixing ability, one of the major problems in electrophotography, there has been studied a toner comprising a resin binder comprising a crystalline polyester (Japanese Patent Laid-Open No. Sho 49-129540 (GB-A-1449363) and the like). However, while the crystalline polyester has an excellent low-temperature fixing ability, the crystalline polyester worsens the pulverizability, the storage ability, the triboelectric stability and the like of the resulting toner when used alone.
In view of this, Japanese Examined Patent Publication No. Hei 5-44029 discloses a toner in which a crystalline polyester is used together with an amorphous resin. However, in this toner, since the backbones of both resins are different, the dispersibility of the crystalline polyester is insufficient, so that there is little effect for improvements in the fixing ability and the storage ability of the toner, and the triboelectric stability also becomes insufficient.
In addition, when the backbones of a crystalline polyester and an amorphous polyester are almost the same, as in the toner disclosed in Japanese Examined Patent Publication No. Sho 62-39428, the dispersibility of the crystalline polyester is so high that a large amount of the crystalline polyester exposed on the surface of the toner causes worsening of the pulverizability and the storage ability.
Further, a combined use of the crystalline polyester with the amorphous polyester has been studied as disclosed in Japanese Patent Laid-Open No. 2001-222138 (U.S. Pat. No. 6,383,705) and Japanese Patent Laid-Open No. Hei 11-249339. In such toners, although an improvement in the low-temperature fixing ability is acknowledged to some extent, further improvements are earnestly desired in the pulverizability, the storage ability and the environmental stability.
An object of the present invention is to provide a toner excellent in all of the pulverizability, the low-temperature fixing ability and the storage ability, and also excellent in the environmental stability.
These and other objects of the present invention will be apparent from the following description.
According to the present invention, there is provided a toner comprising:
a resin binder comprising:
a resin having a ratio of a softening point to a maximal peak temperature of heat of fusion of 0.6 or more and less than 1.1 (hereinafter referred to as xe2x80x9ccrystalline resinxe2x80x9d), and
a hybrid resin having a ratio of a softening point to a maximal peak temperature of heat of fusion of from 1.1 to 4.0 (hereinafter referred to as xe2x80x9camorphous hybrid resinxe2x80x9d); and
a colorant,
wherein the amorphous hybrid resin comprises two polymerization resin components each having an independent reaction path, the two polymerization resin components being partially chemically bonded to each other, wherein at least one of the reaction path of the polymerization resin component is the same as that of the crystalline resin, and wherein a weight ratio of the crystalline resin to the amorphous hybrid resin (crystalline resin/amorphous hybrid resin) is from 1/99 to 50/50.